<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app">
    <div v-if="number == 1">
      A
    </div>
    <div v-else-if="number == 2">
      B
    </div>
    <div v-else>
      C
    </div>
  </div>
</body>

<script src="./node_modules/vue/dist/vue.js"></script>
<script type="text/javascript">
  new Vue({
    el: "#app",
    data() {
      return {
        number: 1
      }
    }
  })

</script>
</html>